1 /* 2 * Copyright (C) 2006, 2007, 2008, 2009 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef V8NodeFilterCondition_h 32 #define V8NodeFilterCondition_h 33 34 #include "bindings/core/v8/ScopedPersistent.h" 35 #include "bindings/core/v8/ScriptState.h" 36 #include "core/dom/NodeFilterCondition.h" 37 #include "platform/heap/Handle.h" 38 #include "wtf/PassRefPtr.h" 39 #include <v8.h> 40 41 namespace blink { 42 43 class Node; 44 class ExceptionState; 45 46 // V8NodeFilterCondition maintains a Javascript implemented callback for 47 // filtering Node returned by NodeIterator/TreeWalker. 48 // A NodeFilterCondition is referenced by a NodeFilter, and A NodeFilter is 49 // referenced by a NodeIterator/TreeWalker. As V8NodeFilterCondition maintains 50 // a Javascript callback which may reference Document, we need to avoid circular 51 // reference spanning V8/Blink object space. 52 // To address this issue, V8NodeFilterCondition holds a weak reference to 53 // |m_filter|, the Javascript value, and the whole reference is exposed to V8 to 54 // let V8 GC handle collection of |m_filter|. 55 // (DOM) 56 // NodeIterator ----RefPtr----> NodeFilter ----RefPtr----> NodeFilterCondition 57 // | ^ | ^ | 58 // weak | weak | ScopedPersistent(weak) 59 // | RefPtr | RefPtr | 60 // v | v | v 61 // NodeIterator --HiddenValue--> NodeFilter --HiddenValue--> JS Callback 62 // (V8) 63 class V8NodeFilterCondition FINAL : public NodeFilterCondition { 64 public: 65 static PassRefPtrWillBeRawPtr<V8NodeFilterCondition> create(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner, ScriptState* scriptState) 66 { 67 return adoptRefWillBeNoop(new V8NodeFilterCondition(filter, owner, scriptState)); 68 } 69 70 virtual ~V8NodeFilterCondition(); 71 72 virtual short acceptNode(Node*, ExceptionState&) const OVERRIDE; 73 74 private: 75 // As the value |filter| is maintained by V8GC, the |owner| which references 76 // V8NodeFilterCondition, usually a wrapper of NodeFilter, is specified here 77 // to hold a strong reference to |filter|. 78 V8NodeFilterCondition(v8::Handle<v8::Value> filter, v8::Handle<v8::Object> owner, ScriptState*); 79 80 static void setWeakCallback(const v8::WeakCallbackData<v8::Value, V8NodeFilterCondition>&); 81 82 RefPtr<ScriptState> m_scriptState; 83 ScopedPersistent<v8::Value> m_filter; 84 }; 85 86 } // namespace blink 87 88 #endif // V8NodeFilterCondition_h 89
